The present invention relates to a medial or a medical-dental treatment chair and to a head support for such a treatment chair.
A treatment chair or a head support of these kinds are described in DE 296 20 801 U1. With this known treatment chair or with this known head support, for the setting of the head support there is provided a pivoting device in the form of a four-bar chain, there being likewise present an associated fixing device for fixing the pivoting device in the respective pivot position. The fixing device has a coupling in the region of the base joint of the four-bar chain, with a coupling element movable between a coupling position and a decoupling position for the selective fixing or blocking and release of the joint. There is provided on the head support a manually movable actuating member for opening and/or closing the coupling, which is connected with the coupling via a cable line. Further, there is associated with the coupling a blocking device having a blocking part which prevents the opening of the coupling when the actuating member is not actuated and allows opening upon actuation of the actuating member.
From EP 0 701 806 A1 there is likewise disclosed a treatment chair or a head support of the kind indicated in the introduction. With this known configuration the pivot device has a link having two joints in its end regions, which by means of its base joint having a head support holder of an associated backrest and in its second joint carries the head support. There is associated with the joints a fixing device having a pneumatic piston cylinder with a working chamber for clamping the joints. The piston cylinder can be acted upon and activated by means of the pneumatic pressure of a hand pump. For a fixing clamping of the joints there is needed a considerable clamping force, since in functional operation the head support is subject to considerable loads which can be applied thereto mainly by the patient and which seek to move the head support. There are thus necessary considerable fixing forces in order to secure the head support in its set position. A further disadvantage of this known configuration consists in that a complex handling procedure is needed to set the head support in the respective desired position. For this, both operating hands are unavoidably needed, the head support being adjusted and positioned with the one operating hand and the pneumatic pressure member being actuated with the other operating hand.
A treatment chair or a head support of the kinds indicated in the introduction is also described in EP 0 673 663 A2. With this known configuration, the pivoting device of the head support is formed by means of a so-called four-bar chain whereby there is associated with the base joint connecting the pivoting device with the backrest a coupling for blocking the joint, which can be opened by means of a manual actuation of an actuating member movably mounted on the head support. The actuating member is, with this known configuration, a tiltably mounted part, which can be tilted with the operating hand. The actuating member is connected with the coupling by means of a cable line, so that the tilting movement can be exploited for opening the coupling.
The object of the invention is, with a treatment chair or a head support of the kinds indicated in the introduction, to improve the support function. The manufacturing outlay and/or the handling effort for adjusting and setting the head support should be small. Further, the head support should be stable in its set position, so that the risk of an unintended movement is avoided or reduced.
These and other object, features, and advantages of the present invention are achieved by a medical of a dental-medical chair and a head support for such a chair. The chair has a backrest and a head support. The head support is pivotally connected with the backrest by a joint device that has a first joint. The joint device can be fixed in a respective pivot position by a fixing device.
The fixing device has a piston cylinder that blocks the associated joint in a set position. Even with greater loads on the head support, the positioning thereof in the set position is ensured. Particularly suitable is a piston cylinder with working chambers that are filled with a fluid such as oil, which has limited compressibility and, therefore, brings about the blocking of the piston cylinder and thus of the joint. For removing this lock a slight effort may be needed. For example, a slight manual actuation may be needed, such as opening a valve in a connection line connecting the working chambers with one another. This measure can be effected with a slight effort or application of force and with a small movement so that the opening and closing of the valve can be readily carried out. Piston cylinders of this kind are per se known components that are obtainable in the market for technical goods and to date have been employed for other purposes.
A further development of the invention makes possible an adjustment and setting of the head support likewise with a slight effort in terms of handling, whereby it is further possible to adjust the head and set it in the desired position support with one-handed operation. Here, the head support can be grasped in a readily manipulable manner, by means of gripping over the grip part carrying the actuating member and over the actuating member, preferably from the side, and the head support can be guided in its setting movement. Thereby the actuating member can be moved, in particular pushed in, into its release position, by means of the thumb of the operating hand or with at least one opposing finger. In this gripping position the head support at the same time finds a firm hold in the operating hand, which makes it possible to move the head support both about the first joint and also about the second joint into the desired support position. In this position there is needed only a pressure release or a letting go of the actuating member, whereby the actuating member is self-actingly moved into its locking position due to its elastic return force, in which locking position the joint is blocked. A further advantage of this configuration consists in that it is suitable both for right-handed and also for left-handed persons.
It is possible to provide the configuration in accordance with the invention for the first joint and/or for the second joint. When respective piston cylinders in accordance with the invention are associated with each of the two joints it is particularly advantageous to provide a common actuating member for both piston cylinders, so that both joints are unlocked by means of the actuation of the actuating member and upon letting go of the actuating member are locked or blocked. With this configuration the head support is settable in a particularly readily manipulable manner, since with a simultaneous movement of both joints selective support positions can be set with one manual movement. In this connection it is moreover of advantage to form the actuating member with an actuating surface extending parallel to the plane of movement of the joints, which actuating surface is so large that is capable of actuating the associated valve members in any pivot position.
Further, the configurations in accordance with the invention distinguish themselves in a simple, compact and economically manufacturable construction, which can be integrated in a simple manner in the setting device and which makes possible a reliable functioning.